Global warming could wipe out large areas of glaciers in the Himalayas and surrounding highlands, threatening livelihoods across much of Asia, climate scientists said in Beijing on Monday.
Rising temperatures fuelled by greenhouse gases from industry and agriculture have already shrunk glaciers on the mountains dividing China and South Asia, experts say.
But one author of a benchmark U.N. report on climate change said more rapid melting could severely disrupt river flows and rainfall patterns across Asia.
"If the rate of temperature rises does not change, glaciers on the Qinghai-Tibet plateau will rapidly shrink, perhaps from 500,000 square kilometers (193,100 square miles) in 1995 to 100,000 square kilometers (38,600 square miles) in 2030," Wu Shaohong of the Chinese Academy of Sciences told a news conference.
Glaciers across the Himalayas and the Qinghai-Tibet Plateau are a major source for rivers such as the Yangtze in China, the Mekong in Indochina and the Ganges in India.
Uncertainty surrounds how fast global warming might shrink glaciers, Wu told reporters after the briefing to explain forecasts issued by the Intergovernmental Panel on Climate Change earlier this month.
Another senior Chinese climate scientist, Qin Dahe, gave a lower estimate, saying that about one-quarter of glaciers in the Qinghai-Tibet Plateau could melt away by mid-century.
But even using conservative forecasts, the experts said the disappearance of glaciers could imperil rain patterns, river flows and farming across Asia. Glacier-fed rivers could swell as the ice melts but then dry out as the ice disappears.
"Glaciers are vital to the national economy and peoples' livelihoods," Qin said, explaining that they were a crucial source of water and had a profound impact on weather across Asia.
India scenario similar
A top Indian climate expert said South Asia would also be threatened if glacier-fed rivers dried up.
"That is the region that is really the granary of South Asia," said Rajendra Pachauri, chairman of the IPCC, referring to the northern part of the Indian subcontinent, which relies on waters from the mountains. Pachauri said underground water supplies would also be at risk from melting glaciers.
"We will have to adapt. We will have to use water far more efficiently than we have in the past," he said, adding that the only hope of slowing global warming was if wealthy countries led the way in dramatically cutting greenhouse gas emissions.
In recent days, China has publicly released its own national assessment of climate change, which forecasts that coverage of glaciers across the country's west could shrink by about 27 percent by mid-century.
As a result, China's assessment warns, "many lakes will swell then shrink, wetlands will retreat, desertification will expand and grasslands will retreat".
China was ready to actively participate in international cooperation on climate change, Xinhua news agency quoted Chinese State Councilor Tang Jiaxuan as saying in talks with visiting British Deputy Prime Minister John Prescott on Monday.
"The Chinese government attaches great importance to the climate change issue and will be guided by the scientific concept on development and follow a new industrialization path to achieve coordinated development between economy and population, resources and environment," he was quoted as saying.
